feat: initialize.

demo/Ursa.Demo/Models/MenuKeys.cs

@@ -14,6 +14,7 @@ public static class MenuKeys
     public const string MenuKeyKeyGestureInput = "KeyGestureInput";
     public const string MenuKeyLoading = "Loading";
     public const string MenuKeyNavigation = "Navigation";
+    public const string MenuKeyNumericUpDown = "NumericUpDown";
     public const string MenuKeyPagination = "Pagination";
     public const string MenuKeyTagInput = "TagInput";
     public const string MenuKeyTimeline = "Timeline";

demo/Ursa.Demo/Pages/NumericUpDownDemo.axaml

@@ -0,0 +1,14 @@
+<UserControl
+    x:Class="Ursa.Demo.Pages.NumericUpDownDemo"
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:u="https://irihi.tech/ursa"
+    d:DesignHeight="450"
+    d:DesignWidth="800"
+    mc:Ignorable="d">
+    <StackPanel>
+        <u:IntUpDown />
+    </StackPanel>
+</UserControl>

demo/Ursa.Demo/Pages/NumericUpDownDemo.axaml.cs

@@ -0,0 +1,15 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using Ursa.Demo.ViewModels;
+
+namespace Ursa.Demo.Pages;
+
+public partial class NumericUpDownDemo : UserControl
+{
+    public NumericUpDownDemo()
+    {
+        InitializeComponent();
+        DataContext = new NumericUpDownDemoViewModel();
+    }
+}

demo/Ursa.Demo/ViewModels/MainViewViewModel.cs

@@ -36,6 +36,7 @@ public class MainViewViewModel : ViewModelBase
             MenuKeys.MenuKeyKeyGestureInput => new KeyGestureInputDemoViewModel(),
             MenuKeys.MenuKeyLoading => new LoadingDemoViewModel(),
             MenuKeys.MenuKeyNavigation => new NavigationMenuDemoViewModel(),
+            MenuKeys.MenuKeyNumericUpDown => new NumericUpDownDemoViewModel(),
             MenuKeys.MenuKeyPagination => new PaginationDemoViewModel(),
             MenuKeys.MenuKeyTagInput => new TagInputDemoViewModel(),
             MenuKeys.MenuKeyTimeline => new TimelineDemoViewModel(),

demo/Ursa.Demo/ViewModels/MenuViewModel.cs

@@ -23,6 +23,7 @@ public class MenuViewModel: ViewModelBase
             new() { MenuHeader = "KeyGestureInput", Key = MenuKeys.MenuKeyKeyGestureInput },
             new() { MenuHeader = "Loading", Key = MenuKeys.MenuKeyLoading },
             new() { MenuHeader = "Navigation", Key = MenuKeys.MenuKeyNavigation },
+            new() { MenuHeader = "NumericUpDown", Key = MenuKeys.MenuKeyNumericUpDown },
             new() { MenuHeader = "Pagination", Key = MenuKeys.MenuKeyPagination },
             new() { MenuHeader = "TagInput", Key = MenuKeys.MenuKeyTagInput },
             new() { MenuHeader = "Timeline", Key = MenuKeys.MenuKeyTimeline },

demo/Ursa.Demo/ViewModels/NumericUpDownDemoViewModel.cs

@@ -0,0 +1,8 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace Ursa.Demo.ViewModels;
+
+public class NumericUpDownDemoViewModel: ObservableObject
+{
+    
+}